CVE-2022-48871

Summary

In the Linux kernel, the following vulnerability has been resolved:

tty: serial: qcom-geni-serial: fix slab-out-of-bounds on RX FIFO buffer

Driver's probe allocates memory for RX FIFO (port->rx_fifo) based on default RX FIFO depth, e.g. 16. Later during serial startup the qcom_geni_serial_port_setup() updates the RX FIFO depth (port->rx_fifo_depth) to match real device capabilities, e.g. to 32.

The RX UART handle code will read "port->rx_fifo_depth" number of words into "port->rx_fifo" buffer, thus exceeding the bounds. This can be observed in certain configurations with Qualcomm Bluetooth HCI UART device and KASAN:

Bluetooth: hci0: QCA Product ID :0x00000010 Bluetooth: hci0: QCA SOC Version :0x400a0200 Bluetooth: hci0: QCA ROM Version :0x00000200 Bluetooth: hci0: QCA Patch Version:0x00000d2b Bluetooth: hci0: QCA controller version 0x02000200 Bluetooth: hci0: QCA Downloading qca/htbtfw20.tlv bluetooth hci0: Direct firmware load for qca/htbtfw20.tlv failed with error -2 Bluetooth: hci0: QCA Failed to request file: qca/htbtfw20.tlv (-2) Bluetooth: hci0: QCA Failed to download patch (-2)

BUG: KASAN: slab-out-of-bounds in handle_rx_uart+0xa8/0x18c Write of size 4 at addr ffff279347d578c0 by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.0-rt5-00350-gb2450b7e00be-dirty #26 Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) Call trace: dump_backtrace.part.0+0xe0/0xf0 show_stack+0x18/0x40 dump_stack_lvl+0x8c/0xb8 print_report+0x188/0x488 kasan_report+0xb4/0x100 __asan_store4+0x80/0xa4 handle_rx_uart+0xa8/0x18c qcom_geni_serial_handle_rx+0x84/0x9c qcom_geni_serial_isr+0x24c/0x760 __handle_irq_event_percpu+0x108/0x500 handle_irq_event+0x6c/0x110 handle_fasteoi_irq+0x138/0x2cc generic_handle_domain_irq+0x48/0x64

If the RX FIFO depth changes after probe, be sure to resize the buffer.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxf9d690b6ece7ec9a6ff6b588df95a010ab2d66f9 < 894681682dbefdad917b88f86cde1069140a047aaffected
LinuxLinuxf9d690b6ece7ec9a6ff6b588df95a010ab2d66f9 < cb53a3366eb28fed67850c80afa52075bb71a38aaffected
LinuxLinuxf9d690b6ece7ec9a6ff6b588df95a010ab2d66f9 < fd524ca7fe45b8a06dca2dd546d62684a9768f95affected
LinuxLinuxf9d690b6ece7ec9a6ff6b588df95a010ab2d66f9 < b8caf69a6946e18ffebad49847e258f5b6d52ac2affected
LinuxLinux5.7affected
LinuxLinux0 < 5.7unaffected
LinuxLinux5.10.165 <= 5.10.*unaffected
LinuxLinux5.15.90 <= 5.15.*unaffected
LinuxLinux6.1.8 <= 6.1.*unaffected
LinuxLinux6.2 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References